Rescorla’s Experiment Contingencies in Classical Conditioning Three Phases Phase 1: Avoidance Conditioning: Establish a behavioral measure (operational definition) of “fear” (intervening variable). Phase 2: Classical Conditioning: Arrange positive, negative, and zero contingencies between tone and shock. Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same.

Rescorla’s Experiment Phase 1: Avoidance Conditioning: Establish a behavioral measure (operational definition) of “fear” (intervening variable). Avoidance behavior is behavior that prevents the occurrence of an aversive stimulus, like shock. Some theories say it is motivated by fear: Avoidance response Fear The avoidance behavior can serve as an operational definition of fear: stronger behavior = more fear.

Rescorla’s Experiment Phase 1: Avoidance Conditioning: Establish a behavioral measure (operational definition) of “fear” (intervening variable). Apparatus: “Shuttle box” Dog jumps over barrier from one compartment to the other to avoid shock. If he stays in one compartment, he gets shocked every 10 seconds (shock-shock, S-S) interval. If he jumps before 10 seconds are up, he’s safe for 30 seconds (response-shock, R-S) interval.

Rescorla’s Experiment Phase 1: Avoidance Conditioning: Establish a behavioral measure (operational definition) of “fear” (intervening variable). Apparatus: “Shuttlebox” If he jumps before the 30 seconds are up, he gets another 30 seconds. But if he messes up and gets shocked, then the S-S interval takes over, and he gets shocked again in 10 seconds. Result: The dogs keep jumping at a steady, moderate pace, and avoid most of the shocks.

Rescorla’s Experiment Phase 1: Avoidance Conditioning: Establish a behavioral measure (operational definition) of “fear” (intervening variable). Apparatus: “Shuttlebox” The rate at which he jumps is the operational definition of fear. The faster he jumps, the more afraid he is. Jumping response Fear

Rescorla’s Experiment Phase 2: Classical Conditioning: Arrange positive, negative, and zero contingencies between tone and shock. US= shock UR= pain CS= tone CR= fear Tones come on at random intervals, averaging 30 seconds. Each lasts 5 seconds. There are three groups that get shocks in different patterns so there is a zero, positive or negative contingency between the shocks and the tones.

Rescorla’s Experiment Phase 2: Classical Conditioning: Arrange positive, negative, and zero contingencies between tone and shock. Group R (random pattern of shocks) There is a zero contingency. The probability of shock right after a tone is the same as it is before tones and between tones. ABCD Note that shocks B and D are paired with tones, but overall the tone has no predictive value.

Rescorla’s Experiment Phase 2: Classical Conditioning: Arrange positive, negative, and zero contingencies between tone and shock. Group P (positive contingency) ABCD Note that Groups P and R get the same number of pairings, important to Pavlov but not Rescorla. Same as Group R except that only shocks that come right after tones get through; there are no shocks before or between tones.

Rescorla’s Experiment Phase 2: Classical Conditioning: Arrange positive, negative, and zero contingencies between tone and shock. Group N (negative contingency) ABCD There are no CS-US pairings in Group N. Same as Group R except that NO shocks due to come right after tones get through, only the shocks before and between tones.

Analyzing Contingencies in Phase 2 This chart summarizes conditions for Groups R, P and N in terms of conditional probabilities. P (US|CS)P (US|no CS)Group Rescorla predicts... PAbove 00Fear CR N0 Above 0Relaxation CR REqual values No CR

Analyzing Contingencies in Phase 2 This chart summarizes conditions for Groups R, P and N in terms of conditional probabilities. P (US|CS)P (US|no CS)Group PAVLOV predicts... PAbove 00 ? N0 ? REqual values ? Fear CR No CR

Rescorla’s Experiment Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same. The contingencies from Phase 2 are discontinued. When the tone comes on, it stays on for 5 seconds, then goes off. The dog gets shocked only if he waits too long to jump, as required by the avoidance procedure. It has nothing to do with the avoidance procedure; it’s just something added on top of it.

Rescorla’s Experiment Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same. The question is: When the tone comes on, does the dog jump faster, slower, or at the same rate as before the tone? Therefore, we can make the following inferences: Rate of jumping is the operational definition of fear.

Rescorla’s Experiment Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same. Jump rate means the tone produced an increase in overall fear. Jump rate means the tone produced a decrease in overall fear. If the rate of jumping doesn’t change, it means there was no CR to the tone.

Rescorla’s Experiment Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same. If the tone has nothing to do with the shocks, how can it increase the animal’s level of fear? ? Total Fear Jump Avoidance procedure Fear CS CR (fear) CR (fear) adds to the fear from the avoidance procedure. It’s total fear that controls jumping.

Rescorla’s Experiment Phase 3: Avoidance Conditioning: Present CS from Phase 2 at random times during avoidance procedure; see if fear increases, decreases, or stays the same. How can the tone decrease the animal’s fear? Avoidance fear Suppose the tone produces a conditioned response of inhibition instead of fear. This inhibition suppresses some of the fear produced by the avoidance procedure. Another term for this inhibition is “relaxation”. - Relaxation response = Less total fear Less total fear means less jumping.

Scorecard: Pavlov Versus Rescorla Here are the results. Who made the right predictions? Rate of jumping... PavlovGroupRescorla PINCREASED NDECREASEDX RNO CHANGEX